Use of Iron Ore Overburden As a Precursor for the Synthesis of an Alkali-activated Binder
Abstract
The iron ore beneficiation process produces a large quantity of waste. Mining companies are looking for technologies that make it possible to dispose of their waste and transform it into raw material for the manufacture of products that can be applied in other areas, for example in the production of concrete, mortar, ceramics, blocks, and bricks. This study aimed at the feasibility of using a calcined iron ore overburden as a precursor of alkali-activated binders. For alkaline activation of the precursors, sodium hydroxide solution and sodium silicate were used in the atomic proportions Al / Na = 2 and Si / Al> 0,7. Mineralogical and microstructural characterization was carried out by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). Tests of compressive strength were performed for the binders with 7, 14, 21 and 28 of curing days. The results of the analyses demonstrated that the properties of the alkali-activated binders produced with the overburden were similar to the binders obtained by precursors used traditionally. It was found, therefore, that the calcined iron ore overburden, can be considered a precursor for obtaining alkaline activated binders
References
[1] T. Bakharev, Resistance of geopolymer materials to acid attack. Cement and Concrete Research, 35 (2005) 658–670.
[2] Melo, C. R., & Riella, H. G. Síntese de zeólita tipo NaA a partir de caulim para obtenção de zeólita 5A através de troca iônica. Cerâmica, 56(340), 340-346 (2010).
[3] A. M. M. Al Bakria, H. Kamarudin, M. BinHussain, I. K. Nizar, Y. Zarina, & A. R. Rafiza, The Effect of Curing Temperature on Physical and Chemical Properties of Geopolymers. Physics Procedia, 22 (2011) 286–291. https://doi.org/10.1016/J.PHPRO.2011.11.045
[4] Davidovits, J. Properties of geopolymer cements, In: Proceedings of the First International Conference Álcaline Cements and Concretes. Ucrânia. p.131- 149 (1994).
[5] A. Hasanbeigi, L. Price, & E. Lin, Emerging energy-efficiency and CO2 emission-reduction technologies for cement and concrete production: A technical review. Renewable and Sustainable Energy Reviews, 16 (2012) 6220–6238. https://doi.org/10.1016/J.RSER.2012.07.019
[6] Borges, P. H. R.; Lourenço, T. M. F.; Foureaux, A. F. S.; Pacheco, L. S. Estudo comparativo da análise de ciclo de vida de concretos geopoliméricos e de concretos à base de cimento Portland composto (CP II),Ambiente Construído, Porto Alegre, v. 14, n. 2, p. 153-168, abr./jun. (2014).
[7] Alves, C. V., Froener, M. S., Longhi, M., Rodríguez, E. D., & Kirchheim, A. P. Avaliação da resistência mecânica em geopolímeros a base de cinza pesada mediante otimização de cura térmica. Ambiente Construído, 15(3), 7-18. Epub September 00, (2015).https://dx.doi.org/10.1590/s1678- 86212015000300022
[8] Davidovits, J. Geopolymers: inorganic polymeric new materials, Journal of Thermal Analysis and calorimetry, 37(8), 1633-1656. (1991).
[9] H. Xu and J.S.J. van Deventer ”The geopolymerization of aluminosilicate minerals”, International Journal of Mineral Processing 59. 247-266 (2000).
[10] N. Sedira, J. Castro-Gomes, & M. Magrinho, Red clay brick and tungsten mining waste-based alkaliactivated binder: Microstructural and mechanical properties. Construction and Building Materials, 190 (2018) 1034–1048. https://doi.org/10.1016/J.CONBUILDMAT.2018.09.153
[11] R. Arellano Aguilar, O. Burciaga Díaz, J.I. Escalante García Lightweight concretes of activated metakaolin-fly ash binders, with blast furnace slag aggregates. Construction and Building Materials, 24 (2010), pp. 1166-1175, https://doi.org/10.1016/j.conbuildmat.2009.12.024